I ran into the same problem with installation ... "machine.config" error. Quickly debugging the installer code showed me that the problem was with an old 1.1 framework that didn't had entries for DBProviders and hence failed.

The workaround to get the current 6.3.1 release installed was to temporary rename the Config directory (to ConfigXXX):

C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\Config

the installation then ran successfully through. Don't forget to rename the directory back to config after that installation!

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